Excessive focus on negative things has traditionally been viewed by competent (genuine) psychotherapists as being a feature of pathology. For example - in the condition known as "borderline schizophrenia" many patients are caught in mode of hyper-awareness of "negative social cues" which skews their mood state toward depression. This becomes a cyclic condition (cyclothymic) in which the paranoid fixations and morbid ideas of reference become engrained as the base personality state.
Consciously focusing on negative perceptions and aspects of experience can be crippling, especially to young or shy or highly impressionable people.